I'm also having considerable (-+ 4 seconds) lag when switching to map view (by pressing M), where before there was none. The mods i'm running are: Kerbal engineer redux, Kopernicus, and of course Galileo's Planet Pack. Naturally I'm running KSP in 64 bit mode. It happens even on low part count rockets, after starting a new game, after a full reinstall. I have no further performance issues.
Hardware: Intel 6500K, 16 GB ram, AMD Radeon 390, Windows 10 running latest patches. KSP is installed on an SSD.
